Waterbeds have, in recent years, come into widespread use throughout the country. A typical waterbed consists of a waterfilled bladder supported within a rigid frame. Although early users of waterbeds were primarily younger people attracted by the novelty and low cost of the apparatus, the use of waterbeds has now spread to a wider range of consumers. Perhaps the most important reason for the popularity of waterbeds is that waterbed mattresses provide uniform sleeping support and eliminate pressure points on which most of a person's weight rests when reclining on conventional sleeping surfaces. In addition, the co-action of the water and the waterbed bladder produces a floating sensation that many people find quite pleasant.
Waterbed manufacturers have been very innovative in providing improvements such as waterbed heaters, elevated frames, and improved bedding material which make waterbeds much more acceptable in the conventional bedding market. However, a major problem with waterbeds to date has been the wave motion set up in the water whenever a person reclines on the bed or changes positions on the bed. Generally, a series of transverse waves are created which are reflected by the lateral walls of the waterbed. As the waves strike the walls, an annoying slapping sound is produced and, because of the reflective action of the walls, the waves generally continue for several seconds before dampening out. A number of inventors have sought to improve the dampening action of waterbeds by providing various insert devices to break up the wave action of the water. Unfortunately, most of the inventions to date have been only modestly effective and tend to impair the sleeping characteristics which have drawn people into the waterbed market. Most prior art devices utilize some sort of baffle arrangement which must be attached to the surface of the waterbed bladder. The surface connection requires heat welding or other attachment means which slows production and increases the cost of the waterbed to the buying public. In addition, the surface attachment sometimes tends to disrupt the co-action of the water and the bladder which produces the floating sensation associated with waterbeds. The use of open-celled foams as a dampening means represents a slightly different approach to the problem. The absorbtion of water within the foam member tends to reduce the wave action of the water by breaking up the volume of the water into a number of interconnected cells. However, a problem with open-celled foam members has been that the foam tends to retain the water and thus, makes it difficult to drain the waterbed after it is initially set up. In addition, the use of thick open-celled members tends to impair the fluid "feel" of the water, causing the waterbed to act like a foam cushion rather than a fluid body.
For these reasons, it can be seen that a need exists for a waterbed dampening system which is easy to fabricate and produce and which will not interfere with the desirable sleeping characteristics of the waterbed. The device should not prevent the waterbed from being easily drained and should be compressible to facilitate folding and storage.